Spherical containers for pressurized fluids

ABSTRACT

A pressurized fluid container of generally spherical shape, wherein at least one depression is provided in a wall of the container for outward expansion should the pressure within the container exceed a nominal value.

United States Patent [151 3,690,500 Remane 1 Sept. 12, 1972 [54]SPHERICAL CONTAINERS FOR 579,867 3/1897 Fenn ..215/1 R PRESSURIZEDFLUIDS 3,399,806 9/1968 Lucas ..222/541 X 2,027,430 1/1936 Hansen..220/66 [721 Invent 5 3. 2,043,339 6/1936 Strickler ..220/66 2,795,3506/1957 Lapin ..220/44 R [73] Assignee: Application Des Gaz, Paris,Seine, 2,894,844 7/1959 Shakman ..220/66 X France 3,037,656 6/1962Humphrey ..220/66 X [22] Filed: Nov. 2, 1970 FOREIGN PATENTS ORAPPLICATIONS [21] Appl. No.: 86,221 1,483,062 6/1967 France ..220/66Primary Examiner-M. Henson Wood, Jr. [52] US. Cl. ..220/1 B, 220/3Assistant Examiner Edwin Gram [51 Int. Cl. ..B65d F25] A 0rney Alexander& Dowel] [58] Field of Search ..220/3, 1 B, 66

6 R f C ed [57] ABSTRACT 't [5 1 e cream I A pressurized fluid containerof generally spherical UNITED STATES PATENTS shape, wherein at least onedepression is provided in a wall of the container for outward expansionshould the g pressure within the container exceed a nominal value.3,152,71 l 10/1964 Mumford ..220/66 X 8 Claims, 7 Drawing FiguresPNENTED 3 690 500 sum 2 nr 3 Q INVENTOR. 1,1 n w;

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PATENTEDSEP 12 m2 sum 3 n5 3 d P INVENTOR.

SPHERICAL CONTAINERS FOR PRESSURIZED FLUIDS This invention concernsspherical containers for pressurized fluids, more particularly, portablecontainers for a pressurized liquefied combustible gas of the type usedin cooking, lighting, domestic heating, travelling and campingapparatus.

It is desirable to use the least possible amount of metal formanufacturing this type of container in order to make it as light inweight as possible and to reduce the manufacturing costs thereof to aminimum, a feature which is particularly important when these containersare disposable, i.e. intended to receive a single charge of pressurizedfluid and to be subsequently thrown away as waste packing when they areempty.

Due to the spherical shape of the container, maximum capacity withminimum wall surface is obtained at the same time as maximum resistanceof these walls to internal over-pressure.

However, since a plain spherical container is not capable of anydeformation liable to increase its capacity, it is not suitable in thisform for the proposed use.

It is also desirable that the condition of such containers should besubject to continuous inspection, particularly when they are stocked inplaces where the temperature could cause the internal pressure to risedangerously.

According to the present invention, a container of generally sphericalshape is characterized in that at least one visible depression isprovided in the side of the container capable of expanding outwardly inthe event of the internal pressure rising above a nominal value, the oreach depression being disposed between the equatorial plane of thecontainer and at least one of its two polar zones which may be reservedfor receiving means of removing fluid and, if desired, for providing astable base.

In one preferred embodiment, the or each depression has the shape of aspherical cup.

It is desirable to provide several such depressions equiangularly spacedover at least one of the hemispheres, about its polar axis, particularlythe upper hemisphere, so that at least one depression is always visiblewhatever may be the position of the observer about the vertical polaraxis of the container.

In order to utilize the cap or cup-shaped depressions for stackingcontainers, four of them should be centered on the same circle about thepolar axis of the upper hemisphere, each of these depressions beingcoaxial with a radius of the container subtending, with the verticalpolar axis thereof, an angle slightly less than 30.

Another depression in the form of a spherical cap may be co-axial withthe pole of the lower hemisphere in order to serve as a stable base forthe container when placed onan even surface.

In a further embodiment of the invention, the or each depression is ofannular form extending around the polar axis of the container.

It may be advantageous to provide several such annular depressionsextending at least over one of the two hemispheres of the container incircles parallel to the equatorial plane thereof.

In another embodiment of the invention, at least the upper hemisphere ofthe container is provided with depressions in the form of a series offolds which converge from the horizontal equatorial plane towards theupper polar zone of the container.

The container may be formed from two hemispheres connected together inair and water-tight relationship by welding, for example, along theirequatorial joining edges, which, being disposed outside the areas of thecontainer deformed by the depressions, retain a strictly circular form,thereby contributing to the strength of the joint, since the stresseswhich the internal pressure of the container may place on this joint arethen strictly limited to hoop stresses.

Alternatively the container may be produced by hydro-forming from asingle sheet of metal the localized depressions in the upper hemisphereof the container then acting to provide the necessary shaping of thesphere.

However, the depressions, whether they are obtained by stamping out,hydroforming or the like, do not reduce the thickness of the material ofthe wall of the container and thus do not affect its strength. They alsoretain their strength when, as a result of internal overpressure in thecontainer, they expand ouwardly since the deformation is effectedwithout stretching and consequential reduction of the wall thickness.Furthermore, this deformation increases the total capacity of thecontainer and, consequently, immediately reduces the internal pressure,thereby increasing the safety of such a container.

The invention will now be described further, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a vertical section through a first embodiment of the containeraccording to the invention;

FIG. 2 is a corresponding plan view;

FIG. 3 shows schematically an arrangement of stacking a number ofcontainers constructed according to another embodiment;

FIG. 4 is an elevational view of another embodiment;

FIG. 5 shows partly in elevation and partly in section, a containerconstructed according to another embodiment of the invention;

FIG. 6 is a view similar to FIG. 5 of a container constructed accordingto yet another embodiment of the invention; and

FIG. 7 is a partial section on the line III-III of FIG. 6.

The drawings show various embodiment of container, all of which are ofgenerally spherical shape and have at least one visible depressioncapable of expanding outwardly in the event of the internal pressurerising above a nominal value, the or each depression being disposedbetween the equetorial plane of the container and at least one of itstwo polar zones which may be reserved for receiving means for theextraction of fluid and, if desired, for providing a stable base.

In the embodiment of the invention shown in FIG. 1, a number ofdepressions 6 have the shape of a spherical cap. Due to this shape, thedepressions give effective resistance to internal pressure without beingsubjected to any deformation until such time as this pressure clearlyexceeds a nominal value, in which case its curvature is reversed,passing from concave to the convex shape, thereby increasing thecapacity of the container and resulting a in reduction of the internalpressure. It

will be noted that this transition from the concave form to the convexform of the depression is effected without stretching and reduction ofthe wall thickness that is to say, without local weakening the wall.

Several equidistant depressions 6 are preferably provided over at leastone of the hemispheres l, 2 about its polar axis, so that at least oneof the depressions 6 remains visible whatever the position of anobserver may be relatively to the axis.

The container of FIG. 1 has two hemispheres 1 and 2 of which each isprovided with several depressions 6 distributed in this manner.

In another particularly advantageous embodiment, the depressions 6 arearranged in such a manner that they may facilitate stacking ofcontainers in a box, for example, or any other packing. For thispurpose, four depressions 6 are provided on only one of the hemispherespreferably the upper hemisphere 1, these spherical cups, centered on aradius of the container, subtending, with the vertical polar axisthereof, an angle slightly less than 30, the depressions themselveshaving a radius of curvature equal to or less than that of thecontainer. I

Each depression 6 can then be used to receive and center a portion ofthe surface of another similar spherical container, as shown in FIG. 3.It may be seen from this Figure that a container A may thus besurrounded by six containers B, the centers of the seven containersbeing located in the plane of the drawing. If the centers of twoadjacent peripheral containers B are connected to that of the containerA, it could be expected that theywould become disposed on the apices ofan equilateral triangle. However, as the upper and lower containers Band the container A penetrate each other partially at the point of theirdepressions 6, while the two containers B situated at the same level asthe container A have no depression at the point where they could comeinto mutual contact with container A, the depressions 6 are designed tobe centered on the radii of the corresponding container which substendwith its vertical polar axis an angle which is not equal to 30, but onlyslightly less, depending on the dimensions of the depressions inquestion.

The polar zone of the upper hemisphere l of the container may be punchedout in its center with an aperture 5 capable of receiving a flap valvedevice with or without a perforable cover. v

Alternatively, the punched hole need not pass through the wall, the baseof the resultant depression itself representing a perforable cover.

The punching may also result in an actual shape, by producing a kind ofsocket capable of then being tapped for receiving the end of a normalgas supply with an automatic flap valve and removable sealing plug.

In some cases it is preferable to provide the lower hemisphere 2 with asingle depression in the form of a spherical cup 6, as shown in FIG. 4,centered on the lower pole of the container and the edge of whichprovides a stable seat for it. As the depression 6' will not be visiblein practice for checking an internal overpressure capable of affectingthe strength of the container, it cannot substitute the depressions 6distributed over the upper hemisphere lin'the manner already describedwith reference to FIGS. 1, 2 and 3.

In any case and whatever embodiment is adopted, the container can bevery readily assembled from two hemispheres l and 2, obtained separatelywith their depression 6 and, if desired, the depression 6' and theaperture 5, by stamping or hydroforming or the like.

It is therefore only necessary to unite the two hemispheres in questionat their respective equatorial edges 3 and 4 by welding, hard solderingor by a mounting arrangement, possibly combined with a welding or hardsoldering operation.

It will be appreciated that the edges 3 and 4 which are remote from thedepressions 6 are perfectly circular, a feature which not onlyfacilitates assembly which may be effected without necessitating angularkeying or alignment of the two hemispheres relatively to each otherabout their common polar axis, but also makes it possible to obtain avery strong air-tight joint,since the stresses resulting from theinternal pressure of the container are exerted on this joint only in theform of hoop stresses and not in the form of local flexing stresses suchas would result from a connecting line deviating from a circular form.

In certain cases, it may be an advantage to provide a form differentfrom that of a spherical cup for the depressions for checking andcompensating internal overpressure.

In the embodiment shown in FIG. 5, depressions 8 are provided in annularform extending about the polar axis of the container and preferablylocated on the upper hemisphere 1. It will be noted that in this caseonly one depression 8 would be sufiicient to indicate to an observer, atany position about the polar axis of the container, an abnormal internalover-pressure by its deformation. I

In the case shown, the upper hemisphere 1 is provided with threedepressions 8 extending around the polar axis in parallel circles.

If, in these conditions, a container charged for example with butane orpropane, is kept in a place where the temperature rises unduly, causinga dangerous rise of the internal pressure, the depressions 8 arere-absorbed, increasing the distance of the upper pole from theequatorial plane, thus giving warning of the danger.

In the embodiment of the invention shown in FIGS. 6 a

and 7, the upper hemisphere 1 of the container is provided with aplurality of elongate depressions 9 which converge from the horizontalequatorial plane towards the upper polar zone of the container.

These depressions 9 which form a series of folds, also demonstrate to anobserver by their deformation, whatever the position of the observer maybe about the polar axis of the container, that the internal pressuretherein may exceed the pressure for which it was designed.

It will be appreciated that, particularly when the depressions areformed by the folds 9, they may facilitate the manufacture of acontainer by hydroforming from a single piece of metal sheeting, sincethey act to accommodate the hammering to which in any case the upperhemispherical wall unit must be subjected above the horizontalequatorial plane of the container in order to provide it with itsspherical shape. It will be appreciated that in all the embodimentsproposed above, it is possible to construct the container of relativelythin metal sheeting by selecting the shape of the depressions to suitthe thickness of said metal sheeting and its mechanical strength inorder to ensure that, in the event of dangerous over-pressure within thecontainer, it can reverse the depressions to provide the outer surfaceof the container with swellings which give an immediately visibleindication of this abnormal situation. In this manner, a kind of alarmsystem is obtained, the pressure of which may be of value for revealingan excess filling, overheating of the containers and so on. Experiencehas shown that the depressions do not weaken the container so that thebursting pressure thereof is no less than that of a similar containerwithout depressions, all other conditions being equal, but that, even ifno notice is taken of the warning given by the appearance of theswellings, said swellings, by increasing the capacity of the container,reduce the danger of the container bursting.

It should be understood that the foregoing description has been givenonly by way of example and in no way limits the scope of the invention,and the described details of construction can be replaced by any otherequivalent details.

I claim:

1. A container of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases, wherein atleast one visible depression is provided in a wall of the container eachsaid depression being capable of expanding outwardly in the event thatthe pressure within the container rises above a nominal value, eachdepression being disposed between the equatorial plane of the containerand at least one of its two polar zones, one of which is reserved forreceiving means for the extraction of fluid;

and wherein a plurality of elongate depressions are formed at least inan upper hemisphere of the container, said depressions being formed by aseries of folds converging from the equatorial plane towards a polarzone of the container.

2. A container of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases wherein thereare provided equi-angularly distributed about its vertical polar axisover at least one hemisphere, depressions in the form of spherical cups,useful for stable stacking up the containers in several levels, onecontainer beside and over others, each container of an upper levelresting at least along a circular edge of one of said depressionsagainst similar containers staggered side by side on a lower level, onecontainer projecting by a part of its general spherical shape into thedepression of another container.

3. A container of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases wherein thereare provided equi-angularly distributed about its vertical polar axisover its upper hemisphere four depressions in the form of sphericalcups, useful for stable stacking up the containers in several levels,one container beside and over others, each container of an upper levelprojecting by a part of its general spherical shape into one of the cupshaped depressions of one of four similar containers arranged side byside on a lower level.

4. A container as specified in claim 3, in which each of saiddepressions is coaxial with a radius of the container which subtendswith the polar axis thereof an angle less than 30.

. A container as specified 11'] claim 3, comprising further in its apex,between the said depressions, means for the extraction of fluid on apart of the container when this means will be preserved from any contactwith adjoining similar containers in stacked up relation.

7. A container of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases, wherein atleast one of the two hemispheres surrounding its vertical polar axiscomprises depressions of annular form extending about said axis incircles parallel to the equatorial plane of the container.

8. A container of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases, wherein atleast one of the two hemispheres surrounding vertical polar axiscomprises a series of folds converging from the equatorial plane towardsa polar zone of the container and which are capable of expandingoutwardly in the event that the pressure within the container risesabove a nominal value, at least one of the two polar zones of thecontainer being reserved for receiving means for extraction of fluid.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,690,500 at d September 12, 1972 Inventor-(s) ROGER REMAN'E It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

- In the heading of the patent between [21] and [52] insert [30] ForeignApplication Priority Dates November 5, 1969 France .69.37960 July 2,1970 France .70.24494 Signed and sealed this 23rd day of January 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR.

ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents FORM PO-lOSO(10-69) USCOMM-DC 60376-1 69 9 U.S. GOVERNMENT FRINTING OFFICE 1969D366334

1. A container of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases, wherein atleast one visible depression is provided in a wall of the container eachsaid depression being capable of expanding outwardly in the event thatthe pressure within the container rises above a nominal value, eachdepression being disposed between the equatorial plane of the containerand at least one of its two polar zones, one of which is reserved forreceiving means for the extraction of fluid; and wherein a plurality ofelongate depressions are formed at least in an upper hemisphere of thecontainer, said depressions being formed by a series of folds convergingfrom the equatorial plane towards a polar zone of the container.
 2. Acontainer of generally spherical shape for pressurized fluids,particularly for pressurized liquefied combustible gases wherein thereare provided equi-angularly distributed about its vertical polar axisover at least one hemisphere, depressions in the form of spherical cups,useful for stable stacking up the containers in several levels, onecontainer beside and over others, each container of an upper levelresting at least along a circular edge of one of said depressionsagainst similar containers staggered side by side on a lower level, onecontainer projecting by a part of its general spherical shape into thedepression of another container.
 3. A container of generally sphericalshape for pressurized fluids, particularly for pressurized liquefiedcombustible gases wherein there are provided equi-angularly distributedabout its vertical polar axis over its upper hemisphere four depressionsin the form of spherical cups, useful for stable stacking up thecontainers in several levels, one container beside and over others, eachcontainer of an upper level projecting by a part of its generalspherical shape into one of the cup shaped depressions of one of foursimilar containers arranged side by side on a lower level.
 4. Acontainer as specified in claim 3, in which each of said depressions iscoaxial with a radius of the container which subtends with the polaraxis thereof an angle less than 30*.
 5. A container as specified inclaim 3, comprising further in its lower hemisphere, around its verticalpolar axis, a depression in the form of a spherical cup, the circularedge of which is useful as a stable seating of the container on asubstantially horizontal plane, so as to place the depressions on theupper hemisphere of the same container all on a same level, on whichthey will receive a part of the generally spherical shaped superposedcontainers of an upper level.
 6. A container as specified in claim 5,comprising further in its apex, between the said depressions, means forthe extraction of fluid on a part of the container when this means willbe preserved from any contact with adjoining similar containers instacked up relation.
 7. A container of generally spherical shape forpressurized fluids, particularly for pressurized liquefied combustiblegases, wherein at least one of the two hemispheres surrounding itsvertical polar axis comprises depressions of annular form extendingabout said axis in circles parallel to the equatorial plane of thecontainer.
 8. A container of generally spherical shape for pressurizedfluids, particularly for pressurized liquefied combustible gases,wherein at least one of the two hemispheres surrounding vertical polaraxis comprises a series of folds converging from the equatorial planetowards a polar zone of the container and which are capable of expandingoutwardly in the event that the pressure within the container risesabove a nominal value, at least one of the two polar zones of thecontainer being reserved for receiving means for extraction of fluid.